[PATCH v2 3/5] src/t_dir_offset2: Add option to create or unlink file

Amir Goldstein
2021-04-25T07:14:54Z

Will be used to test missing/stale entries after modifications to
an open dirfd.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
src/t_dir_offset2.c | 56 ++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 53 insertions(+), 3 deletions(-)

diff --git a/src/t_dir_offset2.c b/src/t_dir_offset2.c
index 7af24519..75b41c1a 100644
--- a/src/t_dir_offset2.c
+++ b/src/t_dir_offset2.c
@@ -34,13 +34,13 @@ static uint64_t d_ino_history[HISTORY_LEN];

void usage()
{
- fprintf(stderr, "usage: t_dir_offset2: [[bufsize] <filename> [-v]]\n");
+ fprintf(stderr, "usage: t_dir_offset2: [[bufsize] [-|+]<filename> [-v]]\n");
exit(EXIT_FAILURE);
}

int main(int argc, char *argv[])
{
- int fd;
+ int fd, fd2 = -1;
char buf[BUF_SIZE];
int nread, bufsize = BUF_SIZE;
struct linux_dirent64 *d;
@@ -49,7 +49,7 @@ int main(int argc, char *argv[])
int retval = EXIT_SUCCESS;
const char *filename = NULL;
int exists = 0, found = 0;
- int verbose = 0;
+ int modify = 0, verbose = 0;

if (argc > 2) {
bufsize = atoi(argv[2]);
@@ -60,6 +60,13 @@ int main(int argc, char *argv[])

if (argc > 3) {
filename = argv[3];
+ /* +<filename> creates, -<filename> removes */
+ if (filename[0] == '+')
+ modify = 1;
+ else if (filename[0] == '-')
+ modify = -1;
+ if (modify)
+ filename++;
if (argc > 4 && !strcmp(argv[4], "-v"))
verbose = 1;
}
@@ -89,6 +96,49 @@ int main(int argc, char *argv[])
exit(EXIT_FAILURE);
}

+ if (modify && fd2 < 0 && total == 0) {
+ printf("getdents at offset 0 returned %d bytes\n", nread);
+
+ /* create/unlink entry after first getdents */
+ if (modify > 0) {
+ if (openat(fd, filename, O_CREAT, 0600) < 0) {
+ perror("openat");
+ exit(EXIT_FAILURE);
+ }
+ exists = 1;
+ printf("created entry %s\n", filename);
+ } else if (modify < 0) {
+ if (unlinkat(fd, filename, 0) < 0) {
+ perror("unlinkat");
+ exit(EXIT_FAILURE);
+ }
+ exists = 0;
+ printf("unlinked entry %s\n", filename);
+ }
+
+ /*
+ * Old fd may not return new entry and may return stale
+ * entries which is allowed. Keep old fd open and open
+ * a new fd to check for stale or missing entries later.
+ */
+ fd2 = open(argv[1], O_RDONLY | O_DIRECTORY);
+ if (fd2 < 0) {
+ perror("open fd2");
+ exit(EXIT_FAILURE);
+ }
+ }
+
+ if (nread == 0) {
+ if (fd2 < 0 || fd == fd2)
+ break;
+
+ /* Re-iterate with new fd leaving old fd open */
+ fd = fd2;
+ total = 0;
+ found = 0;
+ continue;
+ }
+
if (nread == 0)
break;

--
2.31.1